| 1. IntroductionAlong with information society's development, the sensor technology took the highrecent information technology, its vital function is day by day remarkable. The opticalfiber sensor measured the temperatures system in domain and so on industrialproduction and biological medical service has the widespread application prospect, hasthe intellectualized function the optical fiber to measure the temperatures systemspecially. Therefore Develops one kind to have function and so on demonstration,memory, clock, parameter input and main line function intellectualized optical fibersensor measured the temperatures installment and the system have the extremelyimportant righteousness in the project practice.In order to solve this topic, this article has studied in the optical fiber temperaturesurvey system each main constituent characteristic including the optical fibertransmission characteristic, theoretically has analyzed the LED photosource, the lightdetector, the solar battery and the optical fiber coupler characteristic. According toexperimental condition reasonable choice signal optical fiber, solar battery detector,LED photosource and its optical fiber coupling way. And the optical fiber liquidtemperature survey principle which uses to the temperature survey performs to elaborate,also to used the plan to carry on the proof for the most reasonable plan. Has designedthe concrete LED photosource actuation electric circuit, as well as pre-amplifier,subtraction and so on concrete electric circuit. Using the CAN communication main linehad devised two kinds of or two kind of above temperatures pressure survey system,carries on the data the contrast calculation.2,this article studies main workThis article main research work divides into three parts. Have carried on theanalysis to the optical fiber sensor system basic composition component theory and thecharacteristic and to the optical fiber measured the temperatures principle has carried onthe analysis and the design, has designed the SF6 density of gas survey optical fibersensor application system, and carried on the experiment to obtain the experimentalresult and the error analysis.2.1 optical fibers sensor principle and classificationCarry on the analysis to the optical fiber sensor system basic compositioncomponent theory and the characteristic. The photosource uses which to this topic (theLED photosource), optical system and so on light detector, solar battery are partial,performs its principle of work the exhaustive elaboration. Theoretically has analyzed theLED photosource, the light detector, the solar battery as well as the optical fiber couplercharacteristic, this chapter has provided the physical basis for the intelligent optical fibersensor system, has laid the rationale.2.2 optical fibers sensor principle and sensor characteristicDesigned the system path of rays, the photosource actuation electric circuit, thesignal processing and so on three major part electric circuits. In the system path of rays,chose has suited this system photosource, the light detector:In the photosource actuationelectric circuit, has designed the photosource stabilizing circuit, in the signal processing,has designed the signal examination electric circuit.After this system design electric circuit has the input impedance high, the gainadjustment is convenient, the drifting can compensate, in mutually the output signal doesnot contain altogether merit and so on mold signal.2.3 intelligent optical fibers sensor measures the temperatures system applicationdesignThe system to optical fiber sensor measured temperatures measured thetemperatures system the application design, this chapter is the full text key point, tointelligent optical fiber sensor measured the temperatures system has carried on thehardware design.The entire instrument mainly divides into following several parts: Monolithicintegrated circuit system, A/D transforms, D/A transforms, the digital quantity inputoutput, the clock production and the data storage, the liquid crystal display and thekeyboard connection and the CAN main line communication connection and so onseveral partial compositions. The entire functional block diagram sees chart 2.1.Fig 2.1 system functional block diagramThis chapter to intelligent optical fiber sensor measured the temperatures systemhas carried on the design, and resulted in the antijamming ability to the system to carryon the optimized design, enhanced has measured the temperatures system the reliabilityand the antijamming ability. The overall system has timeliness well, the measuringaccuracy high, the reliable line high and the antijamming ability is strong and so on thecharacteristic. The system was the SF6 density of gas survey has provided the effectivesurvey environment.。2.4 optical fibers temperatures examination experiment and analysisMonolithicintegratedcircuitPhotoTransformA/DSwitchLiquidcrystaldisplayKeyboardentryD/ASwitch4-20mAOfibpetircal Analog outputCAN Main lineClock electric circuitThe system design optical fiber temperature sensor had measured the temperaturesdiagram, the optical fiber measured the temperatures gathering system and the sensorsystem unify, the union following diagram has carried on the experiment, and hascarried on the analysis to the empirical datum.Fig. 2.2 optical fibers temperatures sensor measures the temperatures diagramThis system technical specification is:(1) measured the temperatures scope is 30 ℃160 ℃;(2) the measuring error is smaller than 1 ℃, like this basically eliminated themeasurement system the temperature influence factor. Confirmed the system precisionto be high,Timeliness good and the antijamming ability is strong and so on thecharacteristic. Has laid the foundation for the optical fiber SF6 density of gas survey, thistime only needs to obtain the SF6 gas the pressure, then acts according to the SF6density of gas and the temperature pressure relations, can obtain the SF6 gas the density.Did not give unnecessary detail in hereOptical fibertemperature sensorOptical-electricalconverter &lifierLED MultiplexerMeasuredtemperature area(t°C)Ambienttemperature area(T°C)Optical-electricalconverter&lifierConstantpower supply Daimffeprleifnietira lOpticalfiberOpticalfiberOpticalfiberOpticalfiberU3. conclusionHas carried on the hardware design and to the intelligent optical fibertemperature sensor carries on a series of experiments in this test installation foundation,the experimental result had indicated,The system measuring accuracy error is smallerthan 1℃,The entire survey temperature system has the measuring accuracy to behigh,Timeliness good and the antijamming ability is strong and so on the meritBelievedthis intelligent optical fiber temperature sensor system will have the broad applicationprospect in the temperature survey domain. |
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